Quick update :

I updated NC to v12 today
I re-enabled news app and it was throwing errors about non-UTF8 characters in DB.

I searched a bit on the web and found this. news/issues/164

In order to fix the issue with News you have to.

• Disable and remove news app
• Remove news folder in /data
• Drop the news tables in your DB
• Add 'mysql.utf8mb4' => true, to your nextcloud config.php
• Install News app

And the error is gone and your feeds will be updated like before.

Quelle:
https://github.com/nextcloud/news/issues/164#issuecomment-304449076
https://github.com/YunoHost-Apps/nextcloud_ynh/issues/48